* src/qemu/qemu.conf src/qemu/qemu_conf.c src/qemu/qemu_conf.h: there is
  a new config type option for mac filtering
* src/qemu/qemu_bridge_filter.[ch]: new module for the ebtable entry points
* src/qemu/qemu_driver.c: plug the MAC filtering at the right places
  in the domain life cycle
* src/Makefile.am po/POTFILES.in: add the new module